Electrical properties of electronic parts such as an integrated circuit (IC), a large-scale integrated circuit (LSI) and a light-emitting diode (LED) (in other wards, electronic parts using semiconductor elements) are tested by bringing probe pins into contact with electrodes of the semiconductor elements. Such probe pins (contact probe pins) used in test devices (semiconductor test devices) are required not only to have good conductivity (a low contact resistance value), but also to show a stable resistance value (the contact resistance value is not fluctuated) even by repeated contact with surfaces (test surfaces) of the electrodes to be tested.
The contact resistance value of the contact probe pins is generally set to about 100 mΩ or less. However, it is sometimes deteriorated to several hundred mΩ to several Ω by repeated tests on the test surfaces.
As a countermeasure thereto, regular cleaning or replacement of contact terminals has hitherto been carried out. However, this sometimes significantly lowers reliability of a test process and an operating rate, so that other countermeasures have been studied. In particular, a solder material, a Sn-plated electrode or the like has a property of being scraped off to easily adhere to surfaces of the contact terminals because of its softness, and a surface thereof is easily oxidized to cause high resistance, which makes it difficult to perform contact while maintaining a stable resistance value.
As a configuration of the contact probe pin to a metal, on the surface of which a high-resistance oxide film is formed, such as the solder material (for example, lead-free solder such as a SnAgCu alloy) or the Sn-plated electrode, a shape of a tip part thereof tends to be more sharpened, and development thereof has been made based on such a tendency. This is because in order to efficiently remove the oxide film of an other electrode to be brought into contact to maintain a good contact state, it is considered advantageous to have the sharp tip part. Further, even when the electrode material adheres (hereinafter sometimes represented by “Sn adherence”) to the sharp shape, it is also considered that elimination force easily acts thereon.
As such a technology, for example, Patent Document 1 proposes a technology for realizing a reduction of the Sn adherence and efficient removal of an oxide film on a surface of an other electrode by forming a tip into a sharp shape by a specific production method and surface coating with a carbon-containing film. Further, Patent Document 2 proposes a technology for preventing grains scraped off from an other electrode from being deposited onto a tip of a contact probe pin by making a cut in a non-conductive layer of the other electrode with a sharp tip structure. From the viewpoints of efficiently removing the oxide film of the other electrode and preventing grains scraped off from the other electrode from being deposited onto the tip of the contact probe pin, it is a useful configuration to form the tip of the contact probe pin into a sharp shape as described above.
As a material for the contact probe pin, there has been used one in which a surface of a base material such as tungsten (W) or beryllium copper (Be—Cu) having a high hardness is plated with Au, Pd or the like. However, in the contact probe pin composed of this material, an electrode material (particularly, Sn) from a material such as a solder material or Sn plating easily adheres to the tip of the contact probe pin, and the adhered electrode material is surface-oxidized, which causes a problem that the contact resistance value of the contact probe pin becomes unstable.
As a method for reducing the problem due to the Sn adherence as described above to stabilize the contact resistance value, there has also been proposed a technology of coating a vicinity of a tip part of a contact probe pin (a tip part which comes into contact with an electrode and a vicinity thereof) with a carbon film (for example, Patent Documents 3 to 6). In this technology, it is an important requirement that an alloy element such as tungsten (W) is mixed in the carbon film represented by diamond like carbon (DLC) to obtain a surface film having both of low adhesion properties of the carbon film to a test surface (other electrode) and high conductivity resulting from an action of the mixed metal (or a carbide thereof).
On the other hand, as a mounting technology, a ball grid array (BGA) package has been widely used. In such a BGA package, an electrode thereof is in a configuration of halved ball-shaped solder. Further, the number of a mounting configuration of directly forming solder on a semiconductor wafer has increased. With respect to such a three-dimensional electrode, it is possible to realize stable contact by having a plurality of (two or more) projections (particularly, three or more projections). Furthermore, also with respect to an electrode having a flat surface, such as a conventional electrode of an electronic part, it comes to have functions of being able to also cope with a position gap, unanticipated biting of particles and the like by having a plurality of apexes (apex parts of projections).